One of known facsimiles connectable to an information-processing terminal such as a personal computer is disclosed, for example in, Japanese Patent Laid-Open No. 7-288625 which can be connected to an information-processing terminal (a computer device) via bi-directional parallel port such as one from Centronics Data Computer Inc. (IEEE 1284 compliant), or via Universal Serial Bus (USB). In image processing systems having a facsimile and an information-processing terminal that are interconnected using such a scheme, the interconnection is provided only by a mechanism in which a single logical interface is provided on a single physical. Because of this, when using such a information-processing terminal to control a multifunction facsimile having functions such as a printer, a scanner, or a facsimile, the functions of the facsimile cannot operate in parallel, resulting in incomplete uses of the advantages of the multifunction facsimile. In order to force the multifunction facsimile perform multiple functions in parallel, operations described below have to be taken.
Specifically, in the information-processing terminal, header information that identifies each of functions such a printer, a scanner, or a facsimile has to be added to the top of a control command, the command has to be edited and then packetized, and finally the packetized data has to be sent to the multifunction facsimile to designate each of the functions. This leads a big problem in that it requires an effort to rebuild a driver to be installed in the information-processing terminal, that the control operation is complicated, and that throughput is low.
Moreover, in the case of a multifunction facsimile that receives packetized data from an information-processing terminal, analysis of the packetized data is required to determine which the data is to be processed with among a printer and a scanner, or whether the data is for facsimile communication. Furthermore, it is also required that, after a function to be operated is determined on the basis of header information on the top of a control command, the header information be deleted or edited. This caused another big problem of complicated control and low throughput.
Recently, a technique for easily achieving parallel operations of functions such as a printer, a scanner, a digital camera, or a facsimile has been proposed which employs a USB for a physical interface between an information-processing terminal and a facsimile to form multiple logical channels defined by the USB standards (USB composite device). In this case, simpler control and higher throughput can be expected since multiple logical channels corresponding to respective functions are provided; thereby eliminating the requirement that header information for identifying each function be added to a control command.
However, another problem occurs when employing the USB for the physical interface between the information-processing terminal and the facsimile to form multiple logical channels defined by the USB standards. Specifically, in the case of a multifunction facsimile having only a conventional single logical interface, an information-processing terminal adds to the top of an original control command, header information identifying each function such as a printer, a scanner, or a facsimile, and edits and then packetizes the command, and finally sends the packetized data to the multifunction facsimile. Therefore, the multifunction facsimile with a single logical interface does not start operation until it has analyzed the packetized data to determine which the data received from the information-processing terminal is related to among a printer, a scanner, and a facsimile communication. Thus, a main control unit in a multifunction facsimile controls all of the operations; this is why there occurs no trouble caused by conflict between operations requiring the same hardware resource.
However, when the above-described multiple logical channels are used, a control command from an information-processing terminal is directly transferred to operation units without the command analyzed by the main control unit in the multifunction facsimile. This allows the operation units in the multifunction facsimile to independently operate according to instructions from the information-processing terminal. Therefore, when an operator of the multifunction facsimile instructs the main control unit to locally perform an operation that requires a hardware resource such as a scanner or a printer, trouble can occur due to conflicts for the hardware resources between instructions from the information-processing terminal. For example, if there are performed in parallel a printing operation caused by an instruction from the information-processing terminal, and a copying operation caused by an instruction from the operator of the multifunction facsimile, their printing processes at printing unit will conflict with each other.